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WebSphere performance advisors
When gathering runtime information, the WebSphere performance advisors provide diagnostic advice about the environment. The advisors can determine the current configuration for an application server. Then, by trending the runtime data over time, the advisors provide advice about potential environmental changes that can enhance the performance of the system. The advice is hard coded into the system and is based on IBM preferred practices for tuning and performance.
The advisors do not implement any changes to the environment. Instead, they identify the problem and allow the system administrator to make the decision as to whether to implement. Perform tests after any change is implemented.
WebSphere provides the following types of advisors:
Performance and Diagnostic Advisor
This advisor is configured through the Integrated Solutions Console. It writes to the application server log files and to the console while in monitor mode. To minimize the performance impact, configure the server to use HPEL instead of using the
SystemOut.logfile.The interface is configurable to determine how often data is gathered and how often advice is written. It offers advice about the following components:
J2C Connection Manager:
Thread pools
LTC Nesting
Serial reuse violation
Plus various different diagnostic advises
Web Container Session Manager:
Session size with overflow enabled
Session size with overflow disabled
Persistent session size
Web Container:
Bounded thread pool
Unbounded thread pool
Orb Service:
Unbounded thread pool
Bounded thread pool
Data Source:
Connection pool size
Prepared statement cache size
Java virtual machine (JVM):
Memory leak detection
If you need to gather advice about items that are outside of this list, use the Performance Advisor in Tivoli Performance Viewer.
The Performance Advisor in Tivoli Performance Viewer
This advisor is slightly different from the Performance and Diagnostic Advisor. The Performance Advisor in Tivoli Performance Viewer is invoked only through the Tivoli Performance Viewer interface of the Integrated Solutions Console. It runs on the application server that you are monitoring, but the refresh intervals are based on selecting refresh through the console. Also, the output is routed to the user interface instead of to an application server output log file. This advisor captures data and gives advice about more components. Specifically, this advisor can capture the following types of information:
ORB service thread pools
Web container thread pools
Connection pool size
Persisted session size and time
Prepared statement cache size
Session cache size
Dynamic cache size
JVM heap size
DB2 performance configuration
Advisors are more of a tuning aid than a monitoring tool set and are not suitable for use in production environments. But advisors can be a useful aid in identifying well known performance hot spots in the current server configurations in testing.
Advisors are best used when:
A reasonable load can be driven to the application server utilizing significant CPU (50+%).
You want help in tuning a server while establishing initial performance benchmarks.
To view the Advisors window, click the Advisor link in the Tivoli Performance Viewer menu window. The advisor provides advice to the administrator and from the advisors view, the different advice statements can be selected and further analyzed by the administrator, as shown in figure below:
Running the Performance Advisor in Tivoli Performance Viewer requires resources and can impact performance. Use it with care in production environments.
